C.,
Sorry to hear your having a hard time with him sleeping but, remember a child goes through many different phases as they grow. My second son will be 2 in October and will sleep wonderful for weeks then, out of the blue, will wake up over and over again for 2 or 3 nights in a row. I'll think what the heck is going on? Then he settles back into sleeping all night again. It could be your new schedule for him, or perhaps, he's waking up and is a little scared, or maybe he's going through a growth spurt. Many things can be happening, just nurture him through it, he should be back to sleeping all night again soon. Hang in there!
As for potty training, make sure you wait till he shows signs he fully understands what that means. If you start too early, it can make the process very difficult. My first son wasn't ready till he was 2 and about 8 months.
Good luck with everything!!